Balance shaft gears

In modern engines, balance shaft gears balance out vibrations, improve performance and reduce operating noise.

Image of the balance shaft gears in a Volkswagen

Belt force limiter  

The belt force limiter reduces the force of the belt on vehicle occupants from a certain threshold. It works with the belt tensioner and airbags to reduce the risk of injury to front seat passengers’ upper bodies.
To achieve this, a torsion bar is twisted in the belt retractor. The system now releases the belt at a set level of force. The maximum shoulder belt force is reduced and the occupants are restrained more softly by the belt and airbag. This force limiter also reduces impact on occupants without an additional airbag or belt tensioner (e.g. in the rear of the vehicle).

See also:
Belt tensioner

Belt tensioner  

In an accident, the seat belt must restrain vehicle occupants as soon as possible and must therefore be fastened tightly. This is not always the case, particularly due to bulky clothing. This effect is known as slack.
Modern belt tensioners contain a small pyrotechnic charge that tenses the belt when triggered. This eliminates slack.
The belt tensioners are triggered electrically by the airbag control unit and tighten the belt within split seconds. As this now fits more closely to the body, the vehicle occupants are now involved in vehicle deceleration sooner and the impact on the body is evenly distributed across the entire restraint process, reducing the risk of injury.

See also:
Belt force limiter

Schematic diagram of a Volkswagen with belt tensioner detail

Bend lighting 

Dynamic bend lighting is a bi-xenon pivot system that Volkswagen offers in combination with its static cornering light. This illuminates corners better. With dramatically improved illumination, the system ensures up to 90% more safety and a reduced risk of accidents when taking corners. This makes it possible for drivers to perceive the course of the corner and people, animals or obstacles behind the corner much earlier. In critical situations, this buys the driver valuable reaction time.

From a vehicle speed of 10 km/h, the dynamic bend lighting follows the course of road corners with a maximum pivot angle of 15°. The headlights practically light inside the corner. The xenon module on the inside of the corner pivots up to 15° to the inner side of the corner and the module on the outside of the corner pivots up to 7.5° to the outer side of the corner. These angle limits effectively prevent dazzling of oncoming traffic.

See also:
Cornering light
Bi-xenon headlight
‘Dynamic Light Assist’ main beam control

A Volkswagen seen from above at night, driving around a corner. The bend lighting is shown as a beam of light

BEV / Electric car / Electric vehicle / e-vehicle

These terms are used to describe cars driven by current rather than by fuel. Strictly speaking, these terms are even used as generic terms for battery-powered vehicles as well as for fuel cell vehicles. However, generally speaking, “electric vehicle” is almost always used to describe battery electric vehicles (BEVs), driven solely by current.


‘Biturbo’ refers to two inbuilt turbochargers in the motor. The driver benefits from increased torque at the lower end of the engine speed scale and extra performance at the upper end, as well as improved engine responsiveness.

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Schematic diagram of a Volkswagen engine with a built-in turbocharger

Bivalent drive  

Bivalent natural gas models contain a fully-fledged petrol tank as a well as the natural gas fuel tank. This enables a larger combined range than is permitted in areas with a low density of natural gas filling stations.
At outside temperatures lower than minus 10 degrees and immediately after filling with CNG, a petrol-based start is necessary. After a short time, the vehicle switches to running on gas, once the conditions for smooth natural gas operation are met.

See also:
Quasi-monovalent drive

Schematische Darstellung des bivalenten Antiebs in einem VW Golf
Fuel consumption Golf GTI natural gas (CNG), kg/100 km: urban 4.8
– 4.4 / extra-urban 3.1 – 3.0 / combined 3.6 – 3.5; CO₂ emissions
combined (natural gas (CNG)), g/km: 98 - 95; Fuel consumption (petrol),
l/100 km: urban 7.3 – 6.6 / extra-urban 4.6 / combined 5.6 – 5.3; CO₂
emissions combined (petrol), g/km: 127 - 122; efficiency classes: A, A+

Bi-xenon headlights  

The bi-xenon headlight (‘bi’ = two) is an enhancement of the xenon headlight. Both dipped beam and main beam light can be produced with one headlight. A moving shutter blocks off part of the beam of light for dipped beam lighting. When the headlight flasher or main beam is activated, the shutter is removed from the beam of light and the additional light is released.

Front view of the Volkswagen Touareg at night, bi-xenon headlight detail

Blind Spot Sensor  

Radar sensors in the rear monitor the area behind and beside the car. This makes it possible to detect vehicles within a range of 20 metres, within the system’s limitations.
The ‘Blind Spot’ sensor functions from 15 km/h and can inform the driver of another vehicle or object in the warning area using an indicator LED in the exterior mirror. The system indicates the potential hazard with a constant light in the relevant rear view mirror. If the driver operates the turn signal switch nevertheless, the LED light will start flashing more brightly and draw attention to the hazard.
The ‘Blind Spot’ sensor is offered in combination with the Rear Traffic Alert.

See also:
Rear Traffic Alert
‘Side Assist’ lane change system

Image detail of a VW Golf rear view mirror


Bluetooth creates the conditions to allow wireless connection of various portable devices such as mobile phones, notebooks or personal digital assistants (PDA). The connection is a transmission path between the devices’ sending and receiving units.
It can span distances of around 10 metres, enough to connect individual devices within the vehicle. To secure data transmission against intrusion, each Bluetooth device has what is known as a ‘profile’. This profile consists of a globally guaranteed unique identification code which devices communication with each other use to identify themselves. Encryption using a 128-bit code that newly generated on every process offers additional protection when transmitting data. Bluetooth technology is used in systems such as the ‘Business’ mobile phone interface.

Image of the Bluetooth function in a VW Passat

Body galvanisation 

The safest way to protect sheet steel from corrosion is to galvanise it. In galvanisation, the zinc does not form a loose layer on the sheet metal, but reacts to a stable compound that is also not sensitive to surface damage. Galvanisation, which is applied with a very low thickness of less than 20 micrometres (millionths of a metre), is particularly suitable for treating more complex surfaces. It is particularly suitable for the visible surfaces of the vehicle body.

Galvanisation guarantees optimum protection from corrosion and secures the robustness of the structure for its entire service life. The vehicle’s longer lifespan helps make sustainable use of resources.

A VW Passat seen from the side

Body quality 

Practically invisible panel gaps (the narrowest possible spaces) indicate a high level of care taken in processing and body quality. However, the most important quality features of the vehicle body are invisible: these include body rigidity and the passive safety included in a vehicle body (‘crash-proof’ passenger compartment). Good quality also includes robust corrosion protection.

See also:
Crash test
Body rigidity
Passive safety
Passenger compartment
Corrosion protection

A VW Tiguan R-Line on a road at night

Body rigidity 

Body rigidity is a key factor in a car’s safety, comfort and durability. The less a vehicle ‘twists’ on uneven driving surfaces or when taking corners quickly, the higher its torsional rigidity and the safer its driving behaviour.

Rigidity differs depending on the body shape. Generally, the structure of an open-top car cannot achieve the rigidity of a closed vehicle body.

The body structure’s static rigidity is both a key technical parameter and a relevant factor in the subjective feeling of safety and driving comfort. Dynamic rigidity is a key prerequisite for outstanding driving dynamics, good driving comfort and balanced acoustics.

See also:
Body quality

Boot lid, electric  

The electric boot lid is easy to open from the driver’s seat or with the remote control key. It closes by itself when a button in the lid is pressed. The opening height can be adjusted to prevent the lid hitting something, such as the roof of a low garage.

Schematic diagram of a Volkswagen's electric boot lid

Brake energy recuperation (EGPE)

With brake energy recuperation, the energy released during braking or overrun is converted into electrical energy and stored in the battery. This occurs by switching the drive motor to generator mode. The energy obtained in this way is then available again for future acceleration or can supply electrical equipment. This reduces the load on the motor and lowers consumption. Alongside a suitable alternator and battery, the system also consists of an intelligent battery management system, which provides additional monitoring of the battery charge level.

See also:
Energy management

View of an infotainment system, recuperation display

Brake servo (duo)

The brake servo reduces the amount of pedal power the driver needs to apply when braking.
The two-step system ensures sensitive responsiveness. Up to a brake pressure of approx 45 bar, what is known as the comfort braking range, it is reinforced to a factor of 5. If the driver presses more firmly on the brake, the brake force reinforcement is up to tenfold. The driver experiences this through fast-responding braking behaviour with short pedal travel, good controllability and reduced effort up to the ABS control range.

See also:
Hydraulic Brake Assist (HBA)

Image of the brakes on a Volkswagen with focus on the brake servo

Breakover angle 

The breakover angle is the angle up to which the vehicle can drive over a ramp at a slow speed without the underbody touching the edge of the ramp.

See also:
Ramp angle
Cross slope

Schematic diagram of the breakover angle using the Touareg as an example

‘Business’ mobile phone interface 

The ‘Business’ mobile phone interface also meets high standards for comfort. It enjoys direct wireless access to the SIM card thanks to the ‘Bluetooth rSAP’ connection (a suitable mobile phone is required). Alternatively, if the user does not have a ‘Bluetooth rSAP’-ready mobile phone, the ‘Business’ mobile phone interface has a SIM card slot which offers wireless convenience. 
Additional highlights at a glance:

  • Connection to external aerial for maximum reception
  • Integrated Wi-Fi hotspot
  • Storage compartment for inductive charging of smartphones with Qi standard
  • Transfer of active calls to the hands-free system via Bluetooth
  • Operated via voice control, multifunction steering wheel or infotainment system 

See also:
‘Comfort’ mobile phone interface

Interior of a VW Passat with the ‘Business’ mobile phone interface